Unlike many of Verne other novels, this story does not have any science fiction elements. It is an adventure novel.

This novel involves how Joam Garral, a ranch owner who lives near the Peruvian-Brazilian border on the Amazon River, is forced to travel down-stream when his past catches up with him. Most of the novel is situated on a large jangada (a Brazilian timber raft) that is used by Garral and his family to float to Belém at the river's mouth. Many aspects of the raft, scenery, and journey are described in detail.